Field of the Invention
The present invention relates to a thin image pickup apparatus, such as a digital camera.
Description of the Related Art
An image pickup apparatus, such as a digital camera, is required to attain multi-functionality by improving image quality and processing speed in addition to being compact and thin. This increases a heat value of an image pickup device, and requires efficiently dissipating heat generated by the image pickup device.
There is a known technique that perforates a substrate of an image pickup device and arranges an elastic heat dissipation member in the perforated hole so as to contact a back of the image pickup device (see Japanese Laid-Open Patent Publication (Kokai) No. 2012-70272 (JP 2012-70272A)). Heat generated by the image pickup device is conducted to the heat dissipation member and a heat dissipation plate that contacts the heat dissipation member.
Moreover, there is another known technique that attaches a base to a back of an image pickup device package and forms a plurality of fins on a back of the base (see Japanese Laid-Open Patent Publication (Kokai) No. 2008-64863 (JP 2008-64863A)). Heat generated by the image pickup device is conducted to the fins through the base and is dissipated to the inside of an image pickup apparatus.
Incidentally, some image pickup apparatuses in recent years employ small image pickup devices of a BGA (Ball Grid Array) type or a LGA (Land Grid Array) type in order to miniaturize apparatus bodies. Such an image pickup device has electrode pads on the back face thereof and can connect signal lines with a substrate through the electrode pads when the device is implemented.
Since an image pickup device of the BGA type or the LGA type has electrode pads on almost all the back face, a part of the electrode pads cannot connect to a substrate when an area of the substrate on which the image pickup device is implemented is perforated. That is, the heat dissipation structure proposed by JP 2012-70272A cannot be applied to such a type of an image pickup device.
Moreover, an image pickup device and a substrate thereof may be arranged close to another heat source (for example, a main board unit) in a compact and thin image pickup apparatus.
In this case, when heat of the image pickup device is dissipated to the inside of the image pickup apparatus using the technique of JP2008-64863A, the internal temperature of the image pickup apparatus rises rapidly, which may increase the temperature of an IC on the main board unit rapidly, for example. Moreover, when another heat source close to the image pickup device and to the substrate has larger heat value than that of the image pickup device, heat from the other heat source may be conducted to the image pickup device through the fins, which increases the temperature of the image pickup device.
Incidentally, it is necessary to arrange a lens unit having an image pickup device and a main board unit having an image processing circuit, a control circuit, etc. appropriately in a camera body when decreasing a thickness of a digital camera in the vertical direction, Japanese Laid-Open Patent Publication (Kokai) No. H6-326905 (JP H6-326905A) discloses a video camera in which a frame is attached to a side of a lens unit having an image pickup device and a video signal processing board (a main board unit) is arranged to the frame so as to be parallel to the side of the lens unit.
Moreover, Japanese Laid-Open Patent Publication (Kokai) No. 2012-173330 (JP 2012-173330A) discloses an image pickup apparatus in which a shade hood is mounted at a subject side of an exterior member and a circuit board (a main board unit) is arranged in an inside space of the shade hood at the counter side of a subject. The circuit board is arranged at an outer position of one side of the lens unit so as to be parallel to the side of the lens unit.
In both of JP H6-326905A and JP 2012-173330A, the main board unit is arranged at the outer position of one side of the lens unit so as to be parallel to the side of the lens unit. When a digital camera, which is thin in the vertical direction, is going to be achieved by applying such an arrangement, a main board unit will be arranged at an outer position of an upper side or lower side of a lens unit so as to be parallel to the upper side or the lower side of the lens unit.
In this case, the thickness of the digital camera in the vertical direction is at least larger than the total thickness of the lens unit and the main board unit.